Handbook of Information Security Management
(Publisher: CRC Press LLC)
Author(s): Hal Tipton and Micki Krause, Consulting Editors
ISBN: 0849399475
Publication Date: 01/01/98

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CHANGE MANAGEMENT CONTROLS

Additional control over activities by personnel using privileged access IDs can be provided by administrative techniques. For example, the most easily sidestepped control is change control. Therefore, every computing facility should have a policy regarding changes to operating systems, computing equipment, networks, environmental facilities (e.g., air-conditioning, water, heat, plumbing, electricity, and alarms), and applications. A policy is necessary if change is to be not only effective but orderly, because the purpose of the change control process is to manage changes to the computing environment.

The goals of the management process are to eliminate problems and errors and to ensure that the entire environment is stable. To achieve these goals, it is important to:

  • Ensure orderly change. In a facility that requires a high level of systems availability, all changes must be managed in a process that can control any variables that may affect the environment. Because change can be a serious disruption, however, it must be carefully and consistently controlled.
  • Inform the computing community of the change. Changes assumed to affect only a small subsection of a site or group may in fact affect a much broader cross-section of the computing community. Therefore, the entire computing community should receive adequate notification of impending changes. It is helpful to create a committee representing a broad cross-section of the user group to review proposed changes and their potential effect on users.
  • Analyze changes. The presentation of an intended change to an oversight committee, with the corresponding documentation of the change, often effectively exposes the change to careful scrutiny. This analysis clarifies the originator’s intent before the change is implemented and is helpful in preventing erroneous or inadequately considered changes from entering the system.
  • Reduce the impact of changes on service. Computing resources must be available when the organization needs them. Poor judgment, erroneous changes, and inadequate preparation must not be allowed in the change process. A well-structured change management process prevents problems and keeps computing services running smoothly.

General procedures should be in place to support the change control policy. These procedures must, at the least, include steps for instituting a major change to the site’s physical facility or to any major elements of the system’s software or hardware. The following steps should be included:

  1. Applying to introduce a change. A method must be established for applying to introduce a change that will affect the computing environment in areas covered by the change control policy. Change control requests must be presented to the individual who will manage the change through all of its subsequent steps.
  2. Cataloging the change. The change request should be entered into a change log, which provides documentation for the change itself (e.g., the timing and testing of the change). This log should be updated as the change moves through the process, providing a thorough audit trail of all changes.
  3. Scheduling the change. After thorough preparation and testing by the sponsor, the change should be scheduled for review by a change control committee and for implementation. The implementation date should be set far enough in advance to provide the committee with sufficient review time. At the meeting with the change control committee, all known ramifications of the change should be discussed. If the committee members agree that the change has been thoroughly tested, it should be entered on the implementation schedule and noted as approved. All approvals and denials should be in writing, with appropriate reasons given for denials.
  4. Implementing the change. The final step in the change process is application of the change to the hardware and software environment. If the change works correctly, this should be noted on the change control form. When the change does not perform as expected, the corresponding information should be gathered, analyzed, and entered on the change control form, as a reference to help avoid a recurrence of the same problem in the future.
  5. Reporting changes to management. Periodically, a full report summarizing change activity should be submitted to management. This helps ensure that management is aware of any quality problems that may have developed and enables management to address any service problems.

These steps should be documented and made known to all involved in the change process. Once a change process has been established, someone must be assigned the responsibility for managing all changes throughout the process.

HARDWARE CONTROL

Security and control issues often revolve around software and physical needs. In addition, the hardware itself can have security vulnerabilities and exposures that need to be controlled. The hardware access control mechanism is supported by operating system software. However, hardware capabilities can be used to obtain access to system resources. Software-based control mechanisms, including audit trail maintenance, are ineffective against hardware-related access. Manual control procedures should be implemented to ensure that any hardware vulnerability is adequately protected.

When the system control program is initialized, the installation personnel select the desired operating system and other software code. However, by selecting a different operating system or merely a different setup of the operating system (i.e., changing the way the hardware mechanisms are used), software access control mechanisms can be defeated.

Some equipment provides hardware maintenance functions that allow main storage display and modification in addition to the ability to trace all program instructions while the system is running. These capabilities enable someone to update system control block information and obtain system privileges for use in compromising information. Although it is possible to access business information directly from main storage, the information may be encrypted. It is simpler to obtain privileges and run programs that can turn encrypted data into understandable information.

Another hardware-related exposure is the unauthorized connection of a device or communications line to a processor that can access information without interfacing with the required controls. Hardware manufacturers often maintain information on their hardware’s vulnerabilities and exposures. Discussions with specific vendors should provide data that will help control these vulnerabilities.

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